Angle of rotation sensor

An angle of rotation sensor includes a rotary shaft coupled to a permanent magnet. A magnet-sensitive sensor element generates a sinusoidal output signal and a cosinusoidal output signal (Vx, Vy) as a function of the relative angle of rotation (a) between magnet and sensor element. Evaluation electronics generate from the output signals a signal corresponding to the angle of rotation. When the shaft rotates about its axis it moves linearly parallel to its axis along a guide track, and changes the distance between the magnet and sensor. From the sensor signals, a signal (B(z)) is determined, which corresponds to the magnitude of the field strength dependent on the distance. From this signal, a gross signal is determined, from which the number (n) of rotations can be determined. From the sinusoidal and cosinusoidal sensor signals, a fine signal is determined, which is added to the number of rotations multiplied by 360°.